#include <stdio.h>

void permutation1(int a, int b) {
  printf("=== %3d %3d\n", a, b);
  int aux = a;
  a = b;
  b = aux;
  printf("=== %3d %3d\n", a, b);
}

void permutation2(int* a, int* b) {
  printf("### %3d %3d\n", *a, *b);
  int aux = *a;
  *a = *b;
  *b = aux;
  printf("### %3d %3d\n", *a, *b);
}

void main(void) {
  int v1 = 8;
  int v2 = 6;
  printf("::: %3d %3d\n", v1, v2);
  permutation1(v1, v2);
  printf("::: %3d %3d\n", v1, v2);
  printf("\n");
  printf("::: %3d %3d\n", v1, v2);
  permutation2(&v1, &v2);
  printf("::: %3d %3d\n", v1, v2);
  printf("\n");
}